This invention relates generally to seat constructions and more particularly to a seat construction of the type comprising a cushion supported on a relatively rigid support and enclosed by a cover which is secured to the support.
In the seat construction of the indicated type, the cushions typically are made of foam material. In the prior art seat constructions, the foam cushion becomes compressed to take a set as much as ten to fifteen percent after the seat construction has been in use for a period of time. This permanent compression or set of the cushion permits wrinkles to be formed on the cover presenting an unsightly appearance. While a cushion of a very high density or compression characteristic might not take a set, such a cushion would be too hard to provide the seating comfort that most people require.
The softness and compression characteristics of a foam cushion are described in the art in terms of density and/or indentation load deflection (ILD). The lower the density or ILD, the softer the cushion and vice versa.
The seat construction of the invention is designed to overcome the above-described problem of wrinkle production in the cover. In accordance with the invention, the seat construction is formed with a softer region extending along the natural seating line of the seat construction. This is achieved by the provision of a pair of cushions, a first cushion being supported at its bottom surface on a relatively rigid support and having a recessed portion formed in its bottom, and a second cushion being supported at its bottom on the rigid support and contained within the recessed portion of the first cushion. The first cushion is made of a resilient material and the second cushion is made of a resilient material that is softer than the first cushion. A cover e ncloses the outer surface of the first cushion and is secured to the rigid support to complete the seat.
By reason of the above-described seat construction, there is provided a comfortable seat since the user actually "sits into" the seat. Moreover, the design serves to eliminate wrinkles because the hard material forming the outer cushion will not take any significant set. At the same time, along the natural seating line, there is provided a comfortable seating region by reason of the softer insert cushion. The harder outer cushion provides a good support to the user by bolding the legs up to give a comfortable seating feeling whereby the user sits into the seat. In addition, the seat compresses more easily in the region of the natural seating line where the softer insert cushion is provided. Thus, the outer cushion serves to hold the cover in place to prevent the formation of wrinkles while the insert cushion provides a soft seating region extending along the natural seating line of the seat construction. This gives the feeling of softness throughout the entire seat construction.